mitosis

Question 1

is mitosis somatic or sexual?

Answer 1

somatic

Question 2

is meiosis somatic or sexual?

Answer 2

sexual

Question 3

what is the first step of mitosis/meiosis?

Answer 3

replication

Question 4

who discovered DNA?

Answer 4

watson, crick, franklin

Question 5

dna replication

Answer 5

• results in new cells
• happens in nucleus (DNA “unzips” and gets copied –> RNA)
• after replication: 2 identical copies
• semi-conservative replication

Question 6

semi-conservative replication

Answer 6

1 parent strand + 1 new strand

Question 7

base pairing in DNA

Answer 7

adenine (A) + thymine (T)

guanine (G) + cytosine (C)

Question 8

DNA copying

Answer 8

• starts with RNA primer
• 5’ to 3’
• done with help of enzyme (DNA polymerase)
• “mismatch repair” - checks for and corrects mistakes

Question 9

where does DNA copying start?

Answer 9

origin of replication

Question 10

noncoding DNA sequences

Answer 10

transcription/translation regulators
origins of DNA replication
centromeres
telomeres

Question 11

what are telomeres?

Answer 11

to protect genes of eukaryotic chromosomes, special noncoding DNA sequences evolved at end of strands called telomeres

Question 12

describe telomeres?

Answer 12

• no genes
• protect genes from eroding at ends
• shrink each time cell divides
• possibly connected to aging process

Question 13

telomerase

Answer 13

catalyzes lengthening of telomeres in eukaryotic germ cells

Question 14

phase of life of cell

Answer 14

G1, S, G2, mitosis

Question 15

interphase

Answer 15

G1, S, G2

Question 16

G1

Answer 16

beginning of cell’s life, centrioles start dividing, cytokinesis, cells grow to full size, transcription/translation, DNA in single strands

Question 17

S

Answer 17

only DNA replication, 2 double stranded DNA, diploid/haploid cells, no more RNA made (leftovers used for repairs), centrosomes and centrioles replicating, CANNOT DIVIDE WITHOUT THIS

Question 18

G2

Answer 18

nucleus well defined with membrane, centrosomes present (2 centrioles), DNA fully duplicated but in chromatin form, new RNA transcribing for spindle fibers, leftover RNA for repairs

Question 19

what is the most important checkpoint of cell life?

Answer 19

G1

Question 20

centrosome

Answer 20

• area for production/organizing microtubules
• plants: centrosome, no centrioles
• animals: 2 centrosomes, each have 2 centrioles, and move to opposite sides of cell

Question 21

what cells are always in G0?

Answer 21

nerve, muscle, liver cells can be activated to come out of G)

Question 22

do cancerous cells obey checkpoint control?

Answer 22

no

Question 23

what are checkpoints controlled by?

Answer 23

regulatory proteins (p53)

Question 24

how does p53 stop cancer?

Answer 24

• can pause cell cycle, initiate cell DNA repair

- if can’t fix DNA, will induce cell death (apoptosis)

Question 25

apoptosis

Answer 25

programmed cell death

Question 26

what are the 5 stages of mitosis?

Answer 26

prophase, prometaphase, metaphase, anaphase, telophase

Question 27

prophase/prometaphase

Answer 27

DNA condenses, spindle fibers form, centrosomes move to pole, breakdown of nuclear membrane

Question 28

metaphase

Answer 28

chromosomes line up in the middle of the cell, centrioles completely opposites, kinetochore attaches to spindle fiber

Question 29

anaphase

Answer 29

sister chromatids seperate, spindle fibers shorten,

Question 30

telophase

Answer 30

daughter nuclei begin to form, nuclear membrane begins to form, cytokinesis begins (cleavage furrow splits cell into 2 daughter cells), cleavage furrow caused by actin filaments

Question 31

what happens during telophase for plants?

Answer 31

cell wall will form